Corrosion limiting device

ABSTRACT

A corrosion limiting device for use with a fluid-carrying piping system having a connection formed from first and second components. A seal is carried by the components for forming a fluid-tight seal between the components. The components form a groove external of the seal. The corrosion limiting device includes an elongate member having first and second end portions and a length sufficient to extend around the groove. At least a portion of the elongate member is adapted to seat within the groove for aligning the elongate member on the components. The first and second end portions of the elongate member are fastened together. The elongate member serves to inhibit corrosion of the connection.

BRIEF DESCRIPTION OF THE INVENTION

This invention relates to piping systems and more particularly tocorrosion protection systems for fasteners and sealing components usedin piping system connections.

BACKGROUND OF THE INVENTION

Piping systems typically include connections such as flanged joints andvalve body-to-bonnet connections. See, for example, U.S. Pat. Nos.3,334,928; 3,502,356; 4,186,931; 3,400,954; 4,350,350 and 1,035,810.Many of these piping systems conduct corrosive liquids. In such systems,leaks in a piping system connection can result in accelerated corrosionby the process fluid of the fasteners connecting the components of theconnection. Such leaks can result in increased maintenance costs, systeminoperability and/or catastrophic failure of the system connection.

OBJECTS AND SUMMARY OF THE INVENTION

The primary object of the present invention is to provide a device toprotect fasteners and sealing materials by limiting corrosion in theconnection of a piping system.

Another object of the invention is to provide a corrosion limitingdevice of the above character by limiting the amount of oxygen availableto the connection.

Another object of the invention is to provide a corrosion limitingdevice of the above character which creates a substantially airtightbarrier to the space between the components of the connection externalof the main fluid seal.

Another object of the invention is to provide a corrosion limitingdevice of the above character which is longitudinally self-centering onthe connection.

Another object of the invention is to provide a corrosion limitingdevice of the above character which is self compensating to accommodatean offset in the transverse alignment of the connection components.

These and other objects are achieved by a corrosion limiting device foruse with a fluid-carrying piping system having a connection formed fromfirst and second components. A seal is carried by the components forforming a fluid-tight seal between the components. The components form agroove external of the seal. The corrosion limiting device includes anelongate member having first and second end portions and a lengthsufficient to extend around the groove. At least a portion of theelongate member is adapted to seat within the groove for aligning theelongate member on the components. Means is provided for fasteningtogether the first and second end portions of the elongate member. Theelongate member serves to inhibit corrosion of the connection.

Additional objects and features of the invention will appear from thefollowing description from which the preferred embodiments are set forthin detail in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of a connection of a piping systemincorporating the corrosion limiting device of the present invention.

FIG. 2 is a cross-sectional view of the connection of FIG. 1 taken alongthe line 2--2 of FIG. 1.

FIG. 3 a fragmentary view, similar to FIG. 1, of a connection of apiping system incorporating another embodiment of a corrosion limitingdevice of the present invention.

FIG. 4 is a fragmentary view, similar to FIG. 2 and partially cut away,of a connection of a piping system incorporating a further embodiment ofa corrosion limiting device of the present invention.

FIG. 5 is a fragmentary view, similar to FIG. 2 and partially cut away,of a connection of a piping system incorporating yet a furtherembodiment of a corrosion limiting device of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Reference will now be made in detail to the preferred embodiments of theinvention which are illustrated in the accompanying figures. Thedescription of the embodiments of the invention will be followed by adiscussion of their operation.

Corrosion limiting device 11 of the present invention is for use with aconventional fluid-carrying piping system 12 of the type shown in FIGS.1 and 2. System 12 includes first and second pipes 13 and 14 having endswith respective first and second flanges 16 and 17 attached thereto.Pipes 13 and 14 extend along a central longitudinal axis 18 and eachhave a central fluid-carrying passageway 19 extending therethrough alongaxis 18. Each of annular flanges 16 and 17 is formed with a generallyplanar surface or face 23 and an adjoining outer peripheral orcylindrical surface 24 extending at a right angle to face 23. Means inthe form of a plurality of fasteners 26 are provided for securingtogether first and second flanges 16 and 17. Fasteners 26 extend througha corresponding plurality of bores 27 disposed circumferentially aroundthe flanges and opening through opposed faces 23 thereof. Fasteners 26each include an elongate threaded stud 31 having a nut 32 threaded toeach end thereof. A washer 33 is disposed around the stud 31 betweeneach of nuts 32 and flange 16 or 17.

Means is carried by first and second flanges 16 and 17 for providing afluid-tight seal therebetween and includes a conventional spiral woundcircular gasket 41 disposed between opposed faces 23 and a metal ring inthe form of conventional compression stop 42 disposed between faces 23outside gasket 42 and inside studs 31. When flanges 16 and 17 are sosecured together and sealed, faces 23 and compression stop 42 serve todefine a space in the form of annular groove 43 which opens out ontoouter cylindrical surfaces 24. Flanges 16 and 17, fasteners 26, mainsealing gasket 41 and compression stop 42 form a connection 46 in pipingsystem 12.

Corrosion limiting device 11 serves as a barrier carried by flanges 16and 17 for limiting the amount of oxygen that can enter annular groove43. The device 11 is formed from an elongate member 51 made from anon-corrosive material such as stainless steel or a high grade plastic.Elongate member 51 has a length at least equal to the circumferentialdimension of flanges 16 and 17 defined by cylindrical surfaces 24 so asto permit device 11 to extend around the flanges. The material ofelongate member 51 has sufficient flexibility to permit the member tobend around flanges 16 and 17. At least a portion of the elongate memberis adapted to seat within annular groove 43. More specifically, as shownin FIGS. 1 and 2, the elongate member 51 has a T-shaped cross-sectionformed from a longitudinally-extending flange or leg portion 51a adaptedto seat within annular groove 43 and a longitudinally-extending shoulderor band portion 51b which rests on surfaces 24. Leg portion 51a isprovided with a plurality of longitudinally spaced-apart slots ornotches 52 for facilitating bending of elongate member 51. The frequencyand size of the pie-shaped notches 52 is determined by the radius towhich device 11 is to be formed when disposed about flanges 16 and 17.As shown in FIG. 2, elongate member 51 has opposite first and second endportions 53 and 54. Leg portion 51a ends short of first end portion 53so that the end portion 53 can extend over and thus overlap a portion ofsecond end portion 54.

Means is included within corrosion limiting device 11 for securingtogether first and second end portions 53 and 54 and retaining device 11on connection 46. This means consists of a tensioned coil or connectorspring 56 having one end secured to a post 57 extending outwardly fromfirst end portion 53 and a second end secured to a post 58 extendingoutwardly from second end portion 54. It should be appreciated thatother means such as an adhesive (not shown) can be provided for securingtogether end portions 53 and 54 of elongate member 51 and be within thescope of the present invention.

In operation and use, corrosion limiting device 11 is secured toconnection 46 by extending elongate member 51 around the outercylindrical surfaces 24 of first and second flanges 16 and 17. Legportion 51a is faced inwardly towards central axis 18 and seated withinannular groove 43. Leg portion 51a longitudinally centers device 11 onconnection 46 and prevents longitudinal shifting of device 11thereafter. The band portion 51b abuts surfaces 24. End portions 53 and54 are pulled taut relative to each other so that first end portion 53extends over second end portion 54. Connector spring 56 is then attachedto posts 57 and 58 to secure the device 11 to connection 46 and maintaintension on the device 11.

Corrosion limiting device 11 forms a substantially airtight barrierbetween the outer peripheries of flanges 16 and 17 to thus inhibit theingress of oxygen into annular groove 43. The material of elongate body51 is chosen so as to be chemically compatible with the fluid carriedwithin passageways 19 and the temperature range experienced byconnection 46 during operation. Should a leak occur in the seal createdby gasket 41 and fluid from within passageways 19 enter annular groove43, device 11 limits the corrosion to flanges 16 and 17, fasteners 26and compression stop 42 by minimizing the amount of oxygen allowable forthe corrosion process.

Device 11 causes any such leaking fluid to create an equal or slightlypositive pressure within groove 43 relative to the atmospheric pressuresurrounding connection 46. The barrier formed by device 11, and anyrelative positive pressure created thereby, assists in precluding oxygenfrom entering groove 43 through or around device 11. Accordingly, afterthe initial corrosion process has depleted the existing oxygen inannular groove 43, minimal if any further corrosion should occur. Thelow tension exerted longitudinally on device 11 by connector spring 56permits any such leaking fluid to egress annular groove 43 through atleast one opening 60.

Other embodiments of the corrosion limiting device of the presentinvention exist. Corrosion limiting device 66, shown in FIG. 3, is alsofor use on a connection 46. Like reference numerals have been used inFIG. 3 to identify like components shown therein and in FIGS. 1 and 2.Corrosion limiting device 66 includes an elongate flexible member 67which is cylindrical in cross-section and made from any suitableflexible elastomeric material so as to be bendable about flanges 16 and17 and extendable or stretchable in length thereabout. The material ofelongate member 67 is selected so as to be chemically compatible withthe process fluid carried within piping system 12 and the temperaturerange at which device 66 is to be used. Such suitable materials includenitrile. The elongate member 67 has a length sufficient to permit it toextend around outer cylindrical surfaces 24 of first and second flanges16 and 17. More specifically, the opposite first and second ends ofelongate member 67 substantially abut when the member 67 is extended orstretched around surfaces 24 and at least partially seated withinannular groove 43. Elongate member 67 is thus in tension when disposedabout flanges 16 and 17 and seated within groove 43. The diameter ofelongate member 67 is greater than the transverse dimension or width ofannular groove 43 between faces 23 so that only a portion of theelongate member 67 seats within groove 43. Means for securing togetherthe end portions of the elongate member 67 consists of any suitableadhesive such as a cyanoacrylate adhesive.

The operation and use of corrosion limiting device 66 is similar to thatof device 11 discussed above. Device 66 is tensioned when secured toflanges 16 and 17 so as to remain properly positioned within annulargroove 43. The cylindrical conformation of elongate member 67 permitsdevice 66 to self-center longitudinally on flanges 16 and 17. Theseating of at least a portion of device 66 within groove 43 discourageslongitudinal shifting of the device. Member 67 self-compensates andprovides a substantially airtight barrier around groove 43 despite anyoffset transverse alignment of flanges 16 and 17 relative to centrallongitudinal axis 18. O-ring-like member 67 thus serves to create anequal or slightly positive pressure in annular groove 43 relative toatmospheric pressure and limit corrosion to flanges 16 and 17, fasteners26 and compression stop 42. The low tension on member 67 permits anyleaking fluid to egress annular groove 43.

In a further embodiment of the device of the present invention, acorrosion limiting device 76 is provided which is substantially similarto device 66 (see FIG. 4). Like reference numerals have been used inFIG. 4 to identify like components shown therein and in FIGS. 1-3.Corrosion limiting device 76 includes an elongate flexible member 77made from an elastomeric material. Member 77 has an extendible lengthsufficient to permit device 76 to extend around flanges 16 and 17 whenseated within annular groove 43. The elongate member 77 has first andsecond end portions 77a and 77b and a bore 78 extending longitudinallytherethrough so as to be tubular in conformation. Means for fasteningtogether first and second end portions 77a and 77b is provided andconsists of an elongate male plug 81 which is cylindrical in shape. Plug81 is made from any suitable materials such as plastic. One end of plug81 is disposed within bore 78 in first end portion 77a and the other endof the plug is disposed within bore 78 in second end portion 77b. Plug81 is diametrically sized relative to bore 78 so as to slip into bore 78with an interference fit. In addition, a suitable adhesive can beprovided for securing plug 81 to elongate member 77.

In operation and use, corrosion limiting device 76 is secured aroundconnection 46 with at least a portion of elongate member 77 disposedwithin annular grooves 43. Device 76 thus self-centers itself onconnection 46. As discussed above with respect to device 66, thecylindrical shape of elongate member 77 permits device 76 to accommodatetransverse misalignments between first and second flanges 16 and 17.When so disposed on connection 46, device 76 serves to inhibit theingress of oxygen into annular groove 43 and thus limit the corrosionprocess therein should a leak occur in connection 46.

In yet a further embodiment of the device of the present invention, acorrosion limiting device 86 is provided which is similar to devices 66and 76 (see FIG. 5). Like reference numerals have been used in FIG. 5 toidentify like components shown therein and in FIGS. 1-4. Device 86includes an elongate flexible member 87 having an extendible lengthsufficient to permit mounting of the device 86 about flanges 16 and 17.Elongate member 87 has first and second end portions 87a and 87b and abore 88 extending longitudinally therethrough so as to be tubular inconformation. The elongate member 87 consists of an extension springwith an external diameter greater than the transverse dimension ofannular groove 43 in connection 46. Spring 87 is formed from a pluralityof coils 91. It is preferable that spring 87 have a fine wire diameterso as to minimize the leak path through the plurality of opening 90between coils 91. Factors determining the wire diameter of a particularextension spring are the diameter of outer cylindrical surfaces 24 andthe transverse dimension of annular groove 43. The material of extensionspring 87 is chemically compatible with the process fluid carried bypiping system 12 and the operating temperature range of connection 46.Examples of suitable materials are stainless steel and high gradeplastics.

Means for securing together first and second end portions 87a and 87b ofextension spring 87 includes a male plug 92 substantially similar toplug 81. One end of plug 92 is insertable into first end portion 87a andthe other end of the plug 92 is insertable into second end portion 87b,in each case, with an interference fit. An adhesive can be furtherprovided for securing plug 92 to extension spring 87.

Corrosion limiting device 86 operates in substantially the same manneras devices 66 and 76 discussed above to inhibit the amount of oxygenavailable to annular groove 43 and thus limit the corrosion process toconnection 46. Although some spacing may exist between coils 91 ofextension spring 87, such as openings 90, corrosion limiting device 86serves to create a substantially airtight barrier around annular groove43.

It should be appreciated that the corrosion limiting devices describedherein can be used with connections having components other than flangesand be within the scope of the present invention. For example, acorrosion limiting device can be used on a valve body-to-bonnetconnection. In addition, corrosion limiting devices having cylindricalor other conformations can be provided. For example, a cylindricaldevice can be multi-sided in cross-section. Further, the corrosionlimiting devices hereof can have conformations which are not circular,such as triangular or square, so as to accommodate non-circularconnection components.

From the foregoing, it can be seen that a device for limiting corrosionin the connection of a piping system is provided. The device limits theamount of oxygen available to the connection. The device creates asubstantially airtight barrier to the space between the components ofthe connection external of the main fluid seal. The device islongitudinally self-centering on the connection and is self compensatingto accommodate an offset in the transverse alignment of the components.

What is claimed is:
 1. A corrosion limiting device for use in anenvironment with a piping system carrying a fluid and having aconnection formed from first and second components, a seal carried bythe components for forming a fluid-tight seal between the components,the components forming a groove external of the seal, comprising anelongate member having first and second end portions and a lengthsufficient to extend around the groove, at least a portion of theelongate member being adapted to seat within the groove for aligning theelongate member on the components and means for fastening together thefirst and second end portions of the elongate member when the elongatemember is extending around the groove, the elongate member providing atleast one opening between the groove and the environment for permittingany fluid which has leaked from the seal to pass into the environment soas to inhibit the accumulation of any such fluid within the groove, theelongate member having sufficient circumferential continuity forlimiting the ingress of oxygen from the environment into the groove andthus inhibiting corrosion of the connection.
 2. The device of claim 1wherein the elongate member is flexible.
 3. The device of claim 1wherein the elongate member is made from metal.
 4. The device of claim 1wherein the elongate member is made from an elastomeric material.
 5. Thedevice of claim 4 wherein the elongate member is tubular.
 6. The deviceof claim 1 wherein the elongate member is tubular.
 7. The device ofclaim 6 wherein the elongate member is a spring.
 8. The device of claim1 wherein the elongate member has an inwardly extending flange forextending into the groove.
 9. The device of claim 8 wherein the elongatemember is T-shaped in cross-section.
 10. The device of claim 1 whereinthe elongate member includes a band for extending around the components.11. The device of claim 1 wherein the elongate member is bendable intoan annular configuration for extending around the components.
 12. Aconnection in a piping system which is used in an environment to carry afluid comprising first and second components provided with respectivecommunicating passages adapted to carry the fluid, a plurality offasteners carried by the components for securing the componentstogether, a seal carried by the components around the passages forforming a fluid-tight seal between the components, the components havinga space therebetween external of the seal and a barrier carried by thecomponents for separating the space from the environment, the barrierproviding at least one opening between the space and the environment forpermitting any fluid which has leaked from the seal to pass into theenvironment so as to inhibit the accumulation of any such fluid withinthe space, the barrier having sufficient continuity for limiting theamount of oxygen from the environment available to the space and thusinhibiting corrosion within the space.
 13. The connection of claim 12wherein each of the components has an outer peripheral surface, thespace consisting of a groove extending around the components between theouter peripheral surfaces.
 14. The connection of claim 13 wherein atleast a portion of the barrier is disposed in the groove.
 15. Theconnection of claim 12 wherein the barrier is a cylindrical memberextending around the components.
 16. The connection of claim 15 whereinthe cylindrical member is tubular in conformation.
 17. The connection ofclaim 15 wherein the cylindrical member is extendable.
 18. Theconnection of claim 17 wherein the cylindrical member is made from anelastomeric material.
 19. The connection of claim 12 wherein thecomponents are flanges.
 20. The connection of claim 19 wherein theflanges are annular.